Hey, I have not used Windows Defender ever. So cant say much. But I have manually tried steps such as resetting of browser and removing of unwanted extensions that creates plethora of problems making working on PC as hell. However for Trojan, manual removal will not work. I guess you need to refer this: http://www.removemalwarevirus.com/remove-trojanwin32kovter-creg-from-windows-pc

Hey, I have not used Windows Defender ever. So cant say much. But I have manually tried steps such as resetting of browser and removing of unwanted extensions that creates plethora of problems making working on PC as hell. However for Trojan, manual removal will not work. I guess you need to refer this: http://www.removemalwarevirus.com/remove-trojanwin32kovter-creg-from-windows-pc